GRAM1NACEAE (GRASS FAMILY) 



39 a Spikes 2-5 in. long; leaf sheaths clothed with long hairs 



26. Syntherisma. p IIQ 

 b Spikes 1-2 in. long; leaf sheaths not with long hairs 



27. Capriola. p IIQ 



40 a Awns on at least some of the spikelets 41 



b No conspicuous awns on spikelets 62 



41 a Each spikelet on a very slender stalk Vi in. or more long; 



awns about % in. long, straight 



43. Muhlenbergia. p 120 

 b Spikelets not completely as in a 42 



42 a Grass cultivated in the South for its grain, and in green- 



houses 28. Oryza. p IIQ 



b Grasses not as in a 43 



43 a Plant very hairy throughout, velvety, grayish, awn short 



29. Holcus. p IIQ 

 b Plants not completely as in a 44 



44 a Conspicuous awns at least half as long as scale on the 



spikelets 45 



b Short or inconspicuous awns Vs in. or less long on the 



spikelets 56 



45 a Awns at right angles to spikelets and usually twisted 



at the base 46 



b Awns more or less straight with spikelets or sometimes 



bent 47 



46 a 1-3 awns from each spikelet; spikelet i-flowered 



20. Aristida. p IIQ 

 b 4-8 awns from each spikelet; spikelet 4-8-fiowered 



30. Danthonia. p IIQ 



47 a Lower spikelets linear, on club-shaped stalks; awns %-2 



in. long; coarse grass 31. Zizania. p IIQ 



b Plants not completely as in a 48 



48 a Spikelets small, covered with fawn-colored hairs; awns 



twisted 32. Sorgastrum. p IIQ 



b Spikelets not covered with fawn-colored hairs 49 



49 a i awn to each spikelet; spikelets comparatively short.. 50 

 b 2 or more awns to each spikelet; spikelets comparatively 



1( >ng 53 



50 a Cultivated grain; awn bent outward, twisted at base; 



panicle widely spreading 33. Avena. p 120 



b Wild grasses not completely as in a 51 



51 a Panicle 1-3 in. long, very narrow; leaves as long as or 



longer than the stem 34. Oryzopsis. p 120 



b Grasses not completely as in a 52 



52 a Panicle very dense; stems branched at base 



22. Echinochloa. p IIQ 

 b Panicle narrow, not very dense; stems not branched at 



base 35. Arrhenatherum. p 120 



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